Skin Treatment Device and Attachment

ABSTRACT

The present invention is concerned with a skin treatment device that comprises an actuator and at least a skin stimulation element arranged at a mounting structure, the mounting structure being supported at the skin treatment device and the mounting structure being deformable or displaceable against a restoring force when an external force is applied on the skin stimulation element. A contact portion of the mounting structure is arranged to cooperate with the actuator only in a deformed or displaced state of the mounting structure. This renders the device to operate on a low noise level when it is switched on but not pressed against the skin.

FIELD OF THE INVENTION

The present invention is concerned with skin treatment devices ingeneral and in particular with skin treatment devices that comprise astimulation element for mechanically stimulating the skin duringoperation.

BACKGROUND OF THE INVENTION

International patent application WO 01/05267 A1 describes a skintreatment device, namely an epilation device that has a driven means formechanically stimulating the skin during operation of the epilationdevice. The driven means are mounted such that displacement of thedriven means is permitted. The intensity of the mechanical stimulationaffected by the driven means during operation can be varied by the user.

It was found that such a device as described in WO 01/05267 A1 isrelatively noisy and that users may retract from using the epilationdevice because of its “aggressive” noise when it is switched on.

International patent application WO 02/076260 A1 describes a noiseprotection cap that encloses an epilation cylinder and can be pressedagainst the skin with a closed circumference such that the epilationcylinder is sealed inside the noise protection cap during operation. Thedisadvantage of such a noise protection cap is that it obviates a goodsight onto the area that is being treated with the skin treatmentdevice. Further, noise generated by driven means as discussed before isnot reduced when the epilator device is switched on.

SUMMARY OF THE INVENTION

It is hence desirable to improve known skin treatment devices concerningtheir noise behavior.

An improved skin treatment device is provided in accordance with claim1. Further embodiments are defined by the dependent claims.

The proposed skin treatment device Skin treatment device comprises anactuator and at least a skin stimulation element arranged at a mountingstructure, the mounting structure being supported at the skin treatmentdevice. The mounting structure is arranged to be deformable ordisplaceable against a restoring force when an external force is appliedon the skin stimulation element. The mounting structure may thereforecomprise at least a resilient part that e.g. bends under the appliedexternal force or the mounting structure may comprise a spring, e.g. aleaf or helical spring. A contact portion of the mounting structure ispositioned such that it cooperates with the actuator only in a deformedor displaced state of the mounting structure. As the contact portion isnot in contact with the actuator when the skin treatment device isswitched on but not pressed against the skin, the device will operate ata low noise level in the switched-on state. When the device is pressedagainst the skin, the mechanical contact between contact portion andactuator is established and the noise level increases, which isacceptable to a user, as this is in coincidence with the regularoperation of the device. Hence, the proposed skin treatment device ismore appealing to a user than a skin treatment device in which a skinstimulation element is actuated already when the skin treatment deviceis switched on. Support of the mounting structure at the skin treatmentdevice may be established by at least a support structure (e.g. asupport pin) that establishes an essentially fixed point of the mountingstructure when the external force is applied so that the mountingstructure essentially deforms or displaces with respect to the supportstructure.

In an embodiment of the proposed skin treatment device, the skinstimulation element and the mounting structure are part of a detachableattachment.

In a further embodiment, the skin treatment device comprises a drivableskin treatment unit to which the actuator is mechanically coupled sothat driving the skin treatment unit also drives the actuator.

In another embodiment, the external force required to bring the mountingstructure into a deformed or displaced state in which the contactportion cooperates with the actuator lies in the range between about 0.2N and about 5 N. In particular, this range may lie between about 0.5 Nand about 2N.

In an even further embodiment, the skin treatment device is realized asan epilator device, where skin stimulation elements are used to suppressthe pain from plucking out hairs. The skin treatment unit may then berealized as an epilation unit for gripping and pulling out hairs.

The invention is also concerned with a detachable attachment thatcomprises the mounting structure and the skin stimulation element.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further elucidated by explaining an exemplaryembodiment and by reference to figures. In the figures

FIG. 1 shows an exemplary skin treatment device;

FIG. 2 shows a magnified detail of the skin treatment device shown inFIG. 1;

FIG. 3 shows an attachment of the skin treatment device shown in FIGS. 1and 2;

FIG. 4A is side view onto a head part of the skin treatment device asshown in the previous figures that partially is a cut open to show across-sectional cut through the head section in an unloaded state; and

FIG. 4B shows the same details as in FIG. 4A but in a loaded state inwhich an external force is applied onto the head part.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective depiction of an exemplary embodiment of a skintreatment device 1 as proposed, which skin treatment device is realizedas an epilator device. The skin treatment device 1 comprises a handpiece part 10 and a head part 100. The head part 100 comprises adetachable attachment 110 that has an aperture that allows forcontacting the skin during operation of the skin treatment device 1 suchthat hairs growing on the skin can be removed by a skin treatment unit120, which skin treatment unit 120 is here realized as an epilationunit. The attachment 110 further comprises skin stimulation elements111. The skin treatment device 1 is connected to mains voltage via acord 19, but the skin treatment device 1 could also be energized via a(rechargeable) battery that is arranged in the skin treatment device 1.In contrast to the shown embodiment, it is not necessary for the presentinvention that the skin treatment device 1 has a detachable attachment110.

FIG. 2 is a perspective view onto the magnified head of the skintreatment device 1 as shown in FIG. 1 in which details of the head part100 are better visible. The attachment 110 comprises two rows of skinstimulation elements 111 realized as rotatably mounted annuli whereevery other annulus has radially extending spikes for point-likestimulation of the skin during operation of the skin treatment device 1.Each of the rows of skin stimulation elements 111 is mounted on an axis(see FIGS. 4A and 4B). Each end of each of the axes is supported in arecess provided in an outer arm of a mounting structure 113. Furtherskin stimulation elements 112 realized as knobs are arranged on a bridgestructure connecting the outer arms of the mounting structure 113. Theskin treatment unit 120 is realized as an epilation unit comprising anepilation cylinder that is equipped with several pairs of tweezers 121for gripping and pulling out hairs during operation. The epilationcylinder extends into an aperture of the attachment 110 such that hairsgrowing on the skin can be gripped and plucked out during regularoperation when the head part of the epilator device is drawn over theskin. It is to be noted that this specific example is not to be taken aslimiting the invention, but any other realization of a skin treatmentunit 120 should also be covered, specifically any other realization ofan epilation unit. The front row of skin stimulation elements 111 isarranged closer to the skin treatment unit 120 than the back row of skinstimulation elements 111. It was found that such an asymmetricarrangement of rows of stimulation elements leads to an improvedstimulation effect. This can be accounted e.g. to the larger stroke ofthe back row of stimulation elements 111 (this will be explained in moredetail with respect to FIG. 4B).

FIG. 3 is a perspective view onto the attachment 110 as shown in FIG. 2in a detached state. In the shown embodiment, the attachment 110comprises an outer casing 130 that will be fixedly attached to the headpart 100 and an inner casing 131 that is movably mounted in the outercasing 130 to allow a swivel motion of the inner casing 131. Themounting structure 113 is supported by a support pin 135 of the innercasing 131 (the mounting structure 113 is supported by a further supportpin on the opposite side of the aperture, which further support pin isnot visible in the shown view). In the shown embodiment, the mountingstructure 113 is realized as an asymmetric H, wherein the bridgestructure 113 c that connects the two outer arms 113 a and 113 b of theH is arranged with an offset to the vertical centre axis of the H. Skinstimulation elements 112 realized as knobs are arranged on the skin sideof the bridge structure 113 c. A front row and a back row of skinstimulation elements 111 a and 111 b are each arranged on an axis, whereeach axis is supported at an end of the outer arms of the mountingstructure 113 (it is to be noted that only a single skin stimulationelement 111 may be arranged on each axis instead of a plurality of skinstimulation elements as shown). The support pin 135 is further arrangedwith an offset to the vertical centre axis of the H so that the back row111 b of skin stimulation elements is farther away from the support pinthan the front row 111 a of skin stimulation elements. In the discussedembodiment, the skin treatment unit 120 is arranged centered withrespect to the support pins 135 so that the front row and back row ofstimulation elements 111 a and 111 b lead to a stimulation pattern (ordistribution of stimulation events) that is asymmetric with respect tothe skin treatment area during operation. It was found that such anasymmetric stimulation pattern leads to an improved stimulation resultand hence to a better pain suppression for e.g. an epilation treatment.

FIG. 4A is a side view onto a partial cross-sectional cut through thehead part 100. The partial cross-sectional cut is made along line A-A asindicated in FIG. 2. In FIG. 4A, the head part 100 is shown in anunloaded state in which no external forces are applied. The front andback row of stimulation elements 111 a and 111 b as shown in theprevious figures are mounted on a front and a back axis 116 a and 116 b,respectively, where front axis 116 a carries the front row of skinstimulation elements 111 a and back axis 116 b carries the back row ofskin stimulation elements 111 b. Front axis 116 a is extending into anelongated hole 132 of the inner casing 131. Likewise, back axis 116 bmay extend into an elongated hole of the inner casing 131. The mountingstructure 113 is supported by a support pin 135 of the inner casing 131(a further such support pin is arranged opposite to the support pin135). The support pin 135 is arranged asymmetrically so that thedistance of the back axis 116 b to the support pin 135 is larger thanthe distance of the front axis 116 a to the support pin 135. On eachouter arm section of the mounting structure 113 that extends away fromthe support pin 135, a contact portion 114 a and 114 b is arranged. Thecontact portions 114 a and 114 b are arranged symmetrically with respectto the support pin 135. Further, the head part 100 comprises an actuator122 realized as a circular disc having a plurality of angularly spacedprojections 122 a that radially extend over the radius of the disc. Theactuator 122 is fixedly mounted on a central axis 123 that also carriesthe epilation cylinder. During operation of the skin treatment device,the actuator will thus rotate with the speed of the epilation cylinder.In the unloaded state as shown in FIG. 4A, the contact portions 114 donot contact the actuator 122 and specifically not the projections 122 a.In case, the skin treatment device is switched on, the skin treatmentdevice will operate at a low noise level as no mechanical interactionbetween the mounting structure 113 and the actuator 122 is established.

FIG. 4B is the same partial cross-sectional cut through the head part100 of the skin treatment device but shown in a loaded state, where anexternal force F is applied on the mounting structure 113, which isaffected by a user pushing the skin treatment device against the skin.The flexible mounting structure 113 is deformed as a result of theapplied force. Specifically, the outer arm sections of the mountingstructure 113 are bending under the applied force F. In the deformedstate, the contact portions 114 a and 114 b contact the outer surface ofthe actuator 122. During operation, the angularly spaced projections 122a of the actuator 122 induce a vibration of the mounting structure 113and hence a vibration of the skin stimulation elements 111 arranged atthe mounting structure 113, which generates a modulated stimulationexperience on the skin. As the back axis has a larger distance to thesupport pin 135 than the front axis 116 a, the stroke of the back axis116 b is higher and thus the skin stimulation induced by the back row ofskin stimulation elements 111 b is more pronounced than the stimulationinduced by the front row of skin stimulation elements 111 a. As isunderstandable from FIG. 4B, a contact between the contact portions 114a and 114 b and the actuator 122 is only established when the device ispushed against the skin with a certain force. The increase in noiselevel is acceptable to a user as the noise increase coincides with theactive use of the skin treatment device when pressed against the skin.The external force F required bringing the contact portions 114 a and114 b in contact with the actuator 122 may lie in the range of about 0.2N to about 5 N, in particular in the range of about 0.5 N to about 2 N.

In a specific embodiment of the attachment as shown, the outer arms ofthe mounting structure 113 have a width of 1.2 mm and a height of 1 mm.The lengths of the outer arms of the mounting structure between supportpin 135 and the front and back axes 116 a and 116 b, respectively, thatcarry the skin stimulation elements 111 is 9.45 mm and 12.15 mm,respectively. The distance between the nearest edge of the contactportions 114 a and 114 b to the surface of the actuator 122 is 1 mm andthe elasticity modulus is 2000 N/mm2 (polyamide PA66 is chosen asmaterial of the mounting structure). Under these assumptions, the forceF required bringing the contact portions 114 a and 114 b in contact withthe actuator 122 is about 0.67 N and about 1.42 N, respectively. Underthe external force F, the outer arms of the support structure 113 behavelike leaf springs. The skin treatment device is usually pressed againstthe skin with a force of more than 2 N so that the contact portions 114will always get into contact with the actuator 122 during regularoperation of the skin treatment device. In another embodiment only skinstimulation elements 112 realized as knobs are present, which knobs arean integral part of the mounting structure 113.

In an alternative embodiment, a skin stimulation element is mounted on amounting structure that is realized as a helical spring. The springconstant is chosen such that the helical spring is compressed so that arespective contact portion contacts an actuator when pressing the skintreatment device against the skin with a typically applied force. Theactuator may be realized as a vibrator, e.g. as a piezoelectricvibrator.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

1. Skin treatment device comprising: an actuator; and at least a skinstimulation element arranged at a mounting structure, the mountingstructure being supported at the skin treatment device and the mountingstructure being deformable or displaceable against a restoring forcewhen an external force is applied on the skin stimulation element,wherein a contact portion of the mounting structure is arranged tocooperate with the actuator only in a deformed or displaced state of themounting structure.
 2. Skin treatment device according to claim 1,wherein the skin stimulation element and the mounting structure are partof a detachable attachment.
 3. Skin treatment device according to claim1 that further comprises a drivable skin treatment unit to which theactuator is mechanically coupled such that driving the skin treatmentunit also drives the actuator.
 4. Skin treatment device according toclaim 1, wherein the external force necessary to bring the mountingstructure into the deformed or displaced state in which cooperationbetween the contact portion and the actuator is established, lies in therange of about 0.2 N to about 5 N.
 5. Skin treatment device according toclaim 1, wherein the skin treatment device is realized as an epilator.6. Detachable attachment of a skin treatment device, the attachmentcomprising at least a skin stimulation element arranged at a mountingstructure, the mounting structure being supported at the attachment andthe mounting structure being deformable or displaceable against arestoring force when an external force is applied on the skinstimulation element, wherein a contact portion of the mounting structureis arranged to cooperate with an actuator of the skin treatment deviceonly in a deformed or displaced state of the mounting structure when theattachment is in an attached state.